Lawn mower robot and method of controlling the same

ABSTRACT

The present embodiment relates to a lawn mower robot. A lawn mower robot system, comprising: a lawn mower robot disposed with a moving device; a mowing device disposed in the lawn mower robot and mowing lawns; a first communication device disposed in the lawn mower robot and transmitting an inquiry signal for state information; a plurality of boundary display apparatuses, arranged in a lawn presence region, disposed with a second communication device for receiving the inquiry signal for the state information from the first communication device and for transmitting an acknowledge signal for the state information to the first communication device; a controller for recognizing a plurality of absolute coordinates from the lawn presence region based on the acknowledge signal for the state information received from the second communication device and for controlling the mowing device within the limit of the plurality of absolute coordinates.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. 119 and 35U.S.C. 365 to Korean Patent Application No. 10-2011-0077457 (filed onAug. 3, 2011), which is hereby incorporated by reference in itsentirety.

BACKGROUND

The present disclosure relates to a lawn mower robot and a method ofcontrolling the same.

A lawn mower is an apparatus for mowing lawns planted in a home's yardor playground and the like. Such a lawn mower may be classified into atype used at home, and a tractor type used in a wide playground andfarm.

The lawn mower for the home is classified into a walk behind type formowing the lawn while directly dragging the lawn mower from behind, anda directly hand carrying type.

However, there are burdens in that humans should directly operate all oftwo types of the lawn mower. Particularly, since it is difficult to mowthe lawn of a playground by directly operating the lawn mower by an userin today's busy daily life, it is generous to hire outside humans so asto mow the lawns, thereby to generate hiring cost.

SUMMARY

Embodiments provide a lawn mower robot system, and a method ofcontrolling the same.

In one embodiment, a lawn mower robot system comprises a lawn mowerrobot disposed with a moving device; a mowing device disposed in thelawn mower robot and mowing lawns; a first communication device disposedin the lawn mower robot and transmitting an inquiry signal for stateinformation; a plurality of boundary display apparatuses, arranged in alawn presence region, disposed with a second communication device forreceiving the inquiry signal for the state information from the firstcommunication device and for transmitting an acknowledge signal for thestate information to the first communication device; and a controllerfor recognizing a plurality of absolute coordinates from the lawnpresence region based on the acknowledge signal for the stateinformation received from the second communication device and forcontrolling the mowing device within the limit of the plurality ofabsolute coordinates.

In another embodiment, a method of controlling a lawn mower robot systemcomprises transmitting an inquiry signal for state information from afirst communication device disposed in a lawn mower robot to each of aplurality of boundary display apparatuses; receiving an acknowledgesignal for the state information for the inquiry signal for the stateinformation from a second communication device disposed in each of theplurality of boundary display apparatuses in the first communicationdevice; recognizing an absolute coordinate of the lawn mower robot froma lawn presence region when the first communication device receives theacknowledge signal for the state information from all boundary displayapparatuses; and driving a mowing device in the lawn presence regionaccording to the recognized absolute coordinate and mowing lawns.

The details of one or more embodiments are set forth in the accompanyingdrawings and the description below. Other features will be apparent fromthe description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block view for a lawn mower robot according to the presentembodiment.

FIG. 2 is a perspective view for a boundary display apparatus accordingto the present embodiment.

FIG. 3 is a block view for a lawn mower robot according to the presentembodiment.

FIG. 4 is a view for the lawn mower robot system 1 and a lawn presencearea G according to the present embodiment.

FIG. 5 is a flow chart for describing a method of controlling the lawnmower robot system 1 according to the present embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the embodiments of the presentdisclosure, examples of which are illustrated in the accompanyingdrawings.

In the following detailed description of the preferred embodiments,reference is made to the accompanying drawings that form a part hereof,and in which is shown by way of illustration specific preferredembodiments in which the invention may be practiced. These embodimentsare described in sufficient detail to enable those skilled in the art topractice the invention, and it is understood that other embodiments maybe utilized and that logical structural, mechanical, electrical, andchemical changes may be made without departing from the spirit or scopeof the invention. To avoid detail not necessary to enable those skilledin the art to practice the invention, the description may omit certaininformation known to those skilled in the art. The following detaileddescription is, therefore, not to be taken in a limiting sense.

FIG. 1 is a plan view for a lawn mower robot according to the presentembodiment, FIG. 2 is a perspective view for boundary displayapparatuses according to the present embodiment, and FIG. 3 is a blockview for the lawn mower robot according to the present embodiment.

Referring to FIGS. 1 to 3, the lawn mower robot 10 according to thepresent embodiment includes a body 110 having a moving device 120 andforming an appearance, a mowing device 140 disposed in a bottom of thebody 110 and mowing lawns, a sensor 150 disposed in the body 110 andsensing outside information, a power supply 130 supplying power to thelawn mower robot 10, and a controller 160 disposed in the body 110 andcontrolling various electronic parts.

The body 110 forms the appearance of the lawn mower robot 10, andvarious electrical/mechanical parts are received in the inside thereof.The body 110 may be disposed with the power supply 130 for supplyingpower to the lawn mower robot 10.

The power supply 130 may be a chargeable and dischargeable battery (asecond cell). The power supply 130 may be charged by outside power. Thepower supply 130 may be implemented by a replaceable primary cell, andis connected to the outside through lines to receive commercial powersupply. Hereinafter, although it is described that the power supply 130is implemented by the second cell, it is not limited thereto.

The power supply 130 is separately coupled with the body 110, or may bedetachably connected to a charging device (not shown) to be suppliedwith outside current. In this case, the charging device is connected tothe outside power to supply current, and the charging device isinteractively communicated with the lawn mower robot 10 such that thelawn mower robot 10 returns to the charging device for oneself to chargethe power supply 130 by the charging device.

The moving device 120 may move the lawn mower robot 10. The movingdevice 120 may include a plurality of wheels, and a plurality of motorsfor separately driving the plurality of wheels. Rotation velocities ofthe wheels between the plurality of wheels become different byseparately controlling the plurality of motors such that directionswitching is possible. Each of the plurality of motors is bidirectionalrotating motors. Therefore, the lawn mower robot 10 may move forwardedor backward, or left or right.

The sensor 150 may sense objects in the vicinity of the lawn mower robot10, and sense humans, animals, stationary objects or moving objects andthe like.

The sensor 150 may also sense outside temperature or humidity, sunshineintensity, air volume and the like.

The sensor 150 may sense presence or absence of the lawns. The sensor150 may be implemented by the sensor for sensing at least one of color,perfume and spectrum of the lawns.

The sensor 150 may include at least one of a mechanical sensor, anoptical sensor, a chromatic sensor, a radio frequency sensor, acapacitive sensor, an ultrasonic sensor, an infrared ray sensor, a RGBsensor, a spectrum sensor and the like according to the embodiment.

Hereinafter, for example, it is described that the sensor 150 includesthe infrared ray sensor 151 for sensing an infrared ray, and theultrasonic sensor 153 for sensing presence or absence of the boundarydisplay apparatuses 20, but it is limited thereto.

The mowing device 140 is disposed in the body 110, and therefore, mowsthe lawns. The mowing device 140 is disposed in the bottom of the body110, thereby to arrange toward the area having the lawn (hereinafter,refer to ‘the lawn presence area G’). When the mowing device 140 isdriven by a controller 160, the lawns in the lawn presence region G aremowed.

The mowing device 140 may be implemented by a blade type, a circle bladetype, a reel type, a line or strand type formed with a cutter with rope,and other well-known cutter and the like according to the embodiment.

The body 110 is disposed with a first transmitting/receiving device 170.The first transmitting/receiving device 170 may transmit/receivespecific signal at specific frequency from and to outsidetransmitting/receiving devices. Bluetooth, RF (Radio Frequency), IrDA(infrared Data Association), UWB (Ultra Wideband), ZigBee, etc. may beuses as the first transmitting/receiving device 170. It is describedthat the transmitting/receiving devices according to one embodiment ofthe present invention uses RF (Radio Frequency), but it is not limitedthereto.

The first transmitting/receiving device 170 may transmit an inquirysignal for state information for inquiring an on/off state of a secondtransmitting/receiving device 240, inherent identification number forthe second transmitting/receiving device 240, and information for anabsolute position of the second transmitting/receiving device 240 to thesecond transmitting/receiving device 240.

The first transmitting/receiving device 170 may transmit/receive thespecific signal from a mobile terminal etc. including a separate PC(Personal computer), a Remote controller, and a smartphone according tothe embodiment.

The body 110 is disposed with the controller 160. The controller 160controls the electronic/mechanical devices disposed in the lawn mowerrobot 10. The controller 160 controls the above-described moving device120, the mowing device 140, etc., receives data sensed from the sensor150 and the like, then, may store it into a memory 161, and may controlthe electronic/mechanical devices disposed in the lawn mower robot 10based on the stored data.

The controller 160 controls the first transmitting/receiving device 170to transmit an acknowledge signal for the state information, and maycontrol electronic/mechanical devices based on the specific signalreceived from an outside terminal.

Referring to FIGS. 2 and 3, a boundary display apparatuses 20 accordingto the present invention includes a housing 200 for forming anappearance, a photoelectric cell 230 disposed in the housing andproducing current by receiving light, an infrared irradiation unit 210disposed in the housing 200 and irradiating an infrared ray using thecurrent produced from the photoelectric cell 230, and the secondtransmitting/receiving device 240 for interactively communicating withthe transmitting/receiving device 170.

The housing 200 forms the appearance of the boundary display apparatus20. The housing 200 may function as an ornament for a graceful landscapeaccording to the embodiment, and may be formed in various shapes.

In FIG. 2, for an example, it is showed that the housing 200 is formedin a cylindrical shape, but it is not limited thereto.

The photoelectric cell 230 receives the light to produce the current.The photoelectric cell 230 may be disposed in the side or top of thehousing 200. The photoelectric cell 230 may be implemented by a sunlightcell 230 for producing the current by receiving the sunlight, but thekind of the photoelectric cell 230 is not limited. The current producedfrom the photoelectric cell 230 may be stored in a power storage unit(not shown) disposed in the housing 200.

The infrared ray irradiation unit 210 is disposed to allow the infraredray to be irradiated into the outside of the housing 200, and thehousing 200 may be disposed with a plurality of the infrared rayirradiation unit 210. Hereinafter, for example, it is described that twoinfrared irradiation units 210 are spaced apart from each other by apredetermined angle in the housing 200, but the number of the infraredirradiation unit is not limited.

The infrared irradiation unit 210 irradiates the infrared ray into theoutside of the housing 200 using the current produced from thephotoelectric cell 230. The infrared ray to be irradiated is irradiatedin a straight line or may be irradiated in a predetermined angle andrange from the infrared irradiation unit 210. Hereinafter, it isdescribed that the infrared irradiation unit 210 irradiates the infraredray in a straight line, but may irradiate the infrared ray on the twodimensional plan or the three dimensional space in the predeterminedrange and angle.

The boundary display apparatuses 20 may be disposed with a lamp 220emitting the light. The lamp 220 is off by day, and may be operated atnight. The lamp 220 may be operated using the current produced from thephotoelectric cell 230.

As the boundary display apparatuses 20 produce the current using thephotoelectric cell 230, the lawn presence area G to be described latermay be displayed by irradiating the infrared ray from the infraredirradiation unit 210 by day, and the operated lamp 220 may be used as alighting that allows the landscape of the lawn presence area G to begraceful at night.

The boundary display apparatuses 20 are disposed with the secondtransmitting/receiving device 240 capable of interactively communicatingwith the first transmitting/receiving device 170. The secondtransmitting/receiving device 240 may transmit/receive the specificsignal for the first transmitting/receiving device 170. It is describedthat the second transmitting/receiving device 240 uses as the same radiofrequency (RF) as the first transmitting/receiving device 170, but it isnot limited thereto.

When the second transmitting/receiving device 240 receives the inquirysignal for the state information from the first transmitting/receivingdevice 170, the second transmitting/receiving device 240 transmits theinquiry signal for the state information for delivering an on state ofthe second transmitting/receiving device 240, an inherent identificationnumber for the second transmitting/receiving device 240, and informationfor an absolute position of the second transmitting/receiving device 240to the first transmitting/receiving device 170.

That is, the boundary display apparatuses 20 transmit the acknowledgesignal for the state information as a response signal for the inquirysignal for the state information.

FIG. 4 is a view for the lawn mower robot system 1 and a lawn presencearea G according to the present embodiment.

Referring to FIG. 4, the lawn presence area G is defined as the regionhaving the lawn. The region having the lawn is generally partitionedinto a lawns planting region in a certain area to distinguish fromdifferent area at home or in an industrial environment. In this case, aboundary area B is a boundary for separating the lawn presence region Ghaving the lawns and the other remaining area O (outside region). Theboundary area B may form an enclosed path.

Some lawns may be present even on the other remaining region O havingnot the lawns, but, hereinafter, it is described that a lot of lawns arepresent in the lawn presence region G based on the boundary area B andthe other remaining region O includes soil, concrete, block, road andthe like having little lawn or plants.

At least one boundary display apparatuses 20 may be disposed in the lawnpresence region G according to the limit of the lawn presence region.

In FIG. 4, for an example, the lawn presence region G is defined as arectangle by four boundary display apparatuses 20, but it is not limitedthereto.

The boundary display apparatuses 20 display the boundary area B of thelawn presence region G by the infrared ray irradiated from the infraredirradiation unit 210. The boundary display apparatuses 20 form apexes ofeach of the rectangle, the infrared ray irradiated from each of theinfrared ray irradiation unit 210 forms segments of the rectangle, andthe rectangle including the segments and the apexes forms the boundaryarea B. At this time, the region in the inside of the boundary area Bbecomes the lawn presence region G.

The sensor 150 may include the infrared ray sensor 151, and the infraredray sensor 151 may sense the infrared ray irradiated from the infraredirradiation unit 210. The sensor 150 senses the infrared ray whilemoving in the lawn presence region G and transmits the sensed result tothe controller 160.

The sensor 150 may include the ultrasonic sensor 153, and the ultrasonicsensor 153 may sense presence or absence of the boundary displayapparatuses 20. When the sensor 150 meets the boundary displayapparatuses 20 while moving in the lawn presence region G, it senses thepresence or absence of the boundary display apparatuses and therefore,transmits the sensed result to the controller 160.

The controller 160 controls the moving device 120 and/or the mowingdevice 140 according to the sensed result of the sensor 150. When thecontroller 160 receives the sensed result of the infrared ray, thecontroller 160 may control to allow the moving device 120 to be movedalong the boundary area B formed by the infrared ray.

The controller 160 recognizes an absolute coordinate <x,y> of the lawnmower robot 10 in the lawn presence region G by the acknowledge signalfor the state signal received from the second transmitting/receivingdevice 240 of at least one boundary display apparatuses 20. As shown inFIG. 4, when having four boundary display apparatuses 20, a firstboundary display apparatus 20 is indicated as the absolute coordinate<0,0>, a second boundary display apparatus 20 is indicated as theabsolute coordinate <0,1>, a third boundary display apparatus 20 isindicated as the absolute coordinate <1,1>, and a fourth boundarydisplay apparatus 20 is indicated as the absolute coordinate <1, 0>.

The inside limit of the absolute coordinate displayed by the first tofourth boundary display apparatuses 20 forms the above-described lawnpresence region. That is, the sections positioned with the first tofourth boundary display apparatuses 20 corresponds to corners of theboundary area B.

The controller 160 may recognize a current coordinate <x, y> on thebasis of the absolute coordinate corresponding to each corner in thelawn presence region G. The controller 160 recognizes the currentcoordinate <x,y> by calculating distance or direction etc. with thesecond transmitting/receiving device 240 in each corner.

Further, the controller 160 compares arrival velocity of the acknowledgesignal for the state information transmitted to the firsttransmitting/receiving device 170 or strength of signal transmitted fromthe second transmitting/receiving device 240, etc. and therefore, mayrecognize the current absolute coordinate <x, y>.

The controller 160 recognizes the current coordinate <x, y> of the lawnmower robot in the absolute coordinates <0,0>, (1,0), <1,1>, <0,1>, anddrives the mowing device 140 within the limit of the absolute coordinatedisplayed by the first to fourth boundary display apparatuses 20.

In the case that the body 110 is deviated from the lawn presence regionG, the controller 160 may stop the mowing device 140. The controller 160may recognize to allow the body 110 to be deviated from the lawnpresence region G by the current coordinate in the situations, to be notproduced commonly, such as slidingness due to a slope or a compulsorymovement caused by an outside situation while moving the lawn mowerrobot.

When the body 110 is deviated from the lawn presence region G, the body110 may be overturned, and the mowing device 140 disposed in the bottomof the body 110 may be exposed outside. In this case, the controller 160stops the mowing device 140 to prevent an user, an outside or pets andplants from injuring or damaging by the mowing device 140

Further, when the body 110 is deviated from the lawn presence region G,the controller 160 may stop the moving device 120.

FIG. 5 is a flow chart for describing a method of controlling the lawnmower robot system 1 according to the present embodiment.

Referring to FIG. 5, the method of controlling the lawn mower robotsystem 1 is described.

First, the lawn mower robot 10 is turned on. The lawn mower robot 10 isinitially turned on in the lawn presence region G, or the lawn mowerrobot 10 is turned on outside the lawn presence region and then it maybe moved into the lawn presence region G.

When the lawn mower robot 10 is turned on, the controller transmits theinquiry signal for the state signal from the firsttransmitting/receiving device 170 disposed in the lawn mower robot 10 toall the boundary display apparatuses 20 (S10).

As described above, the inquiry signal for the state information mayinclude signals for inquiring the on/off state of the secondtransmitting/receiving device 240, the inherent identification numberfor the second transmitting/receiving device 240, and information forthe absolute position of each of the second transmitting/receivingdevice 240.

That is, the second transmitting/receiving device 240 disposed in eachof the first to fourth boundary display apparatuses 20 receives theinquiry signal for the state information in the present embodiment.

The second transmitting/receiving device 240 disposed in each of thefirst to fourth boundary display apparatuses 20 transmits the responsesignal for the inquiry signal for the state information, that is, theacknowledge signal for the state information to the firsttransmitting/receiving device 170.

The acknowledge signal for the state information may include the onstate of the second transmitting/receiving device 240, the inherentidentification number for the second transmitting/receiving device 240,and the information for the absolute position.

The first transmitting/receiving device 170 receives the acknowledgesignal for the state information from the second transmitting/receivingdevice 240 disposed in each of the boundary display apparatuses 20(S20).

Further, the controller 160 determines whether it receives theacknowledge signal for the state information from the secondtransmitting/receiving device 240 of all the boundary displayapparatuses 20 (S30).

At this time, the number of the boundary display apparatuses 20 may bealready input to the lawn mower robot 10 through an input section.

On determining at step S30, when the acknowledge signal for the stateinformation is not received from at least one secondtransmitting/receiving device 240, an error message is informed from thelawn mower robot to the outside (S80). The user recognizes the errormessage informed outside, and repairs the second transmitting/receivingdevice 240 included in the boundary display apparatuses 20.

On determining at step S30, when the acknowledge signal for the stateinformation is received from the second transmitting/receiving device240 of all the boundary display apparatuses 20, the controller 30recognizes the absolute coordinate of the lawn mower robot in the lawnpresence region G (S40).

In this case, as shown in FIG. 4, the current absolute coordinate in thelawn presence region is recognized on the basis of four boundary displayapparatuses 20. The controller 160 recognizes the absolute coordinate<x, y> for the current position within the limit of at least threeabsolute coordinates displayed by the first to fourth boundary displayapparatuses 20, drives the mowing device 140 within the limit of theabsolute coordinate displayed by the first to fourth boundary displayapparatuses 20, and then, mows the lawn in the lawn presence region G(S50).

After recognizing the absolute coordinate, on mowing the lawn or movingin the lawn presence region G, the error from the absolute coordinate ofthe lawn mower robot 10 may be caused by the slope of the ground orobstacle or trespassing humans or animals.

When the error is caused from the absolute coordinate, the error iscaused on driving the mowing device 140 by the lawn mower robot 10 inthe lawn presence region G, and therefore, the mowing device 140 may bedriven outside the lawn presence region G as well.

To prevent this, the controller 160 determines whether the error iscaused from the absolute coordinate of the lawn mower robot 10 (S60).When the error is not caused from the absolute coordinate, the currentoperation is continually implemented (S70), and the mowing device 140 iscontinually driven and the lawns are continually mowed as an embodiment.

When the error is caused from the absolute coordinate, the controller160 controls the first transmitting/receiving device 170 to transmit theinquiry signal for the state information to the secondtransmitting/receiving device 240 of all the boundary displayapparatuses 20 again.

The first transmitting/receiving device 170 transmits the inquiry signalfor the state information to all the second transmitting/receivingdevice 240 again, and the second transmitting/receiving device 240 whichreceives the inquiry signal for the state information transmits theacknowledge signal for the state information to the firsttransmitting/receiving device 170 again.

The first transmitting/receiving device 170 receives the acknowledgesignal for the state information from each of the secondtransmitting/receiving device 240 again (S20). The controller 160analyzes the acknowledge signal for the state information received fromthe second transmitting/receiving device 240, thereby to determine theabsolute coordinate again.

According to an embodiment of the present invention, the lawn mowerrobot is disposed with the first transmitting/receiving device and theboundary display apparatuses are disposed with the secondtransmitting/receiving device. Therefore, since the firsttransmitting/receiving device is interactively communicated with thesecond transmitting/receiving device, the lawn mower robot determinesthe absolute position in the lawn presence region for oneself to mow thelawns.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

What is claimed is:
 1. A lawn mower robot system, comprising: a lawnmower robot disposed with a moving device; a mowing device disposed inthe lawn mower robot and mowing lawns; a first communication devicedisposed in the lawn mower robot and transmitting an inquiry signal forstate information; a plurality of boundary display apparatuses, arrangedin a lawn presence region, disposed with a second communication devicefor receiving the inquiry signal for the state information from thefirst communication device and for transmitting an acknowledge signalfor the state information to the first communication device; and acontroller for recognizing a plurality of absolute coordinates from thelawn presence region based on the acknowledge signal for the stateinformation received from the second communication device and forcontrolling the mowing device within the limit of the plurality ofabsolute coordinates.
 2. The lawn mower robot system according to claim1, wherein the first and second communication device use a radiofrequency.
 3. The lawn mower robot system according to claim 1, whereinthe controller stops the mowing device when the lawn mower robot isdeviated from the limit of the plurality of absolute coordinates.
 4. Thelawn mower robot system according to claim 1, wherein each of theplurality of boundary display apparatuses include an infrared rayirradiation unit for displaying the lawn presence region to irradiate aninfrared ray.
 5. The lawn mower robot system according to claim 4,wherein the lawn mower robot includes a sensor for sensing the infraredray irradiated from the infrared ray irradiation unit.
 6. The lawn mowerrobot system according to claim 1, wherein the controller determines acurrent coordinate on the basis of the plurality of absolutecoordinates.
 7. The lawn mower robot system according to claim 1,wherein when the first communication device does not receive theacknowledge signal for the state information from at least one of theplurality of the boundary display apparatuses, the lawn mower robotgenerates an error message.
 8. The lawn mower robot system according toclaim 7, wherein the lawn mower robot is disposed with an input sectionfor inputting the number of the boundary display apparatuses.
 9. Amethod of controlling a lawn mower robot system, comprising:transmitting an inquiry signal for state information from a firstcommunication device disposed in the lawn mower robot to each of aplurality of boundary display apparatuses; receiving an acknowledgesignal for the state information for the inquiry signal for the stateinformation from a second communication device disposed in each of theplurality of boundary display apparatuses in the first communicationdevice; recognizing an absolute coordinate of the lawn mower robot froma lawn presence region when the first communication device receives theacknowledge signal for the state information from all the boundarydisplay apparatuses; and driving a mowing device in the lawn presenceregion according to the recognized absolute coordinate and mowing lawns.10. The method according to claim 9, wherein when the firstcommunication device does not receive the acknowledge signal for thestate information from at least one of the plurality of the boundarydisplay apparatuses, the lawn mower robot generates an error message.11. The method according to claim 9, further comprising inputting thenumber of the boundary display apparatuses to the lawn mower robot. 12.The method according to claim 9, the controller stops the mowing devicewhen the lawn mower robot is deviated from the limit of the plurality ofthe absolute coordinates.
 13. The method according to claim 9, thecontroller stops the moving device for moving the lawn mower robot whenthe lawn mower robot is deviated from the limit of the plurality of theabsolute coordinates.
 14. The method according to claim 9, thecontroller recognizes the absolute coordinate again when the lawn mowerrobot is deviated from the limit of the plurality of absolutecoordinates.